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Changing the Orientation of the Projectile, ADVANCED

To have more control over the projectile's orientation, it is necessary to turn on the viewing window's toolbar. This has many options. The first section below will cover the options that you will use 90% of the time. This will be followed by the full explaination of all of the options.

The 90% solution will include rotating the projectile in any plane and also bringing the viewing window closer to or further away from the projectile

  1. Locate the check box below the viewing window with the caption Navigation Bar
  2. Check the box and look at the navigation bars to the left and below the projectile.
  3. The buttons are labeled on the screen if the visualizer is viewed as a full screen.
  4. Click on the button marked Study. It may already be selected
  5. Now click on the button marked Turn
  6. Now click on the center of the projectile AND hold the mouse button DOWN
  7. As you drag the mouse (still holding the button down) up or down or left or right, the projectile will spin about the initial point you clicked on.
  8. It is important to note that dragging the mouse sets the speed and direction of motion. Once the desired speed and direction are reached simply holding the mouse button down will keep the motion contant. Releasing the mouse Button will stop the motion. This mouse behavior holds true for all of the modes of operation. The arrows can be used in combination with the depressed mouse as an alternative to step in any direction.
  9. To get closer (or further away), click on the button marked Plan
  10. Now click on the projectile window AND hold the mouse button DOWN
  11. As you drag the mouse (still holding the button down) up or down, the projectile will advance or retreat.
  12. As you drag the mouse left or right, the projectile will spin about its CG.
  13. Experiment with these two modes until you get a nice isometric looking view. We will use that for the next section of the tutorial.
  14. If you ever loose sight of the projectile, you can return it back to the start by selecting the button marked Restore

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© 2002 Arrow Tech Associates

Footnote: All the Details - Optional

The following explaination was provided with the display software. It is not necessary to read or master all of the following options.

Cortona User's Guide

The following sections contain the description of the Cortona main controls:  

The Cortona Window

With Cortona you can see and explore 3D worlds. Cortona will start automatically when you open a file containing VRML world. There are two parts of the Cortona window: 
  1. Toolbars:
    • The vertical toolbar, which contains buttons used to specify navigation type in a world.
    • The horizontal toolbar, which contains buttons with predefined actions to change your position in a world.
  2. The 3D window, which shows VRML world.
There is also  pop-up menu, which you access by pressing the right mouse button while the pointer is over toolbars or 3D window.

Some worlds do not allow you navigating in a world, so toolbars may be invisible.

Navigating in Cortona

Moving through a 3D Space is similar to moving a camera. Think of a video camera that captures images in the real world and converts them into electronic signals for viewing on a screen; it has a position and orientation, and these are independent attributes.Your movements in the world continually position and orient that camera. Use the camera controls on the vertical toolbar to move the camera through the 3D Space.

This concept assumes that there is a real person viewing and interacting with the VRML world. Nevertheles, the VRML author may place any number of viewpoints (or cameras) in the world - interesting places from which the user might wish to view the world. Only one viewpoint may be active at a time. This section describes the mechanisms that Cortona provides for navigating in a three-dimensional space.

Using Viewpoints

A viewpoint describes a position and orientation for viewing the scene. The VRML author will probably want to guide the user to the best vantage points for viewing it. Not all worlds contain viewpoints, but when they do, you can use them.

To activate a viewpoint:

  •   Click the VIEW in the horizontal toolbar or choose viewpoints from the pop-up menu, and then select a viewpoint from the list of the predefined viewpoints.

  • Click the arrow buttons to move to the next or previous viewpoint. You can also press Page Down or Page Down keyboard button.
Note:
If there are no predefined viewpoints in a world, the Empty message appears.

Moving around: Walk, Fly, and Study

There are three main navigation modes that Cortona offers: WALK, FLY, and STUDY. You can switch the navigation mode by clicking buttons on the vertical toolbar. Each navigation mode may have several options: PLAN, PAN, TURN, and ROLL. The combination of navigation mode and its option determines the possible camera motion and its orientation. Please note that the VRML author has an opportunity to specify which navigation paradigm should be used in the scene by default. Some worlds don't allow the user to use navigation controls, but they may provide on-screen cues to navigation.

You can navigate with the mouse, the keyboard, or both mouse and keyboard. To move around a 3D world using the mouse:  

  1. Choose a navigation mode.
  2. Position the pointer anywhere in the 3D window and press the left mouse button.
  3. Move the mouse while holding down its left button. The direction in which you drag the mouse determines the camera motion.
  4. Release the left mouse button to stop moving.

Note: The distance that you drag the mouse determines the speed with which the camera moves. If you stop moving the mouse, the camera will continue moving until you release the mouse button. To accelerate the camera's movement or rotation, press SHIFT, CTRL or SHIFT+CTRL.


  and  
Use WALK+PLAN to move in a horizontal plane.

Forward - move closer
Backward - move further
Right - turn to the right
Left - turn to the left

Note: Move the mouse forward or backward while holding down the Space key to turn upward, downward.
Move the mouse left or right while holding down the ALT key to move left or right.


 and 
Use WALK+PAN to move left or right in a horizontal plane.

Forward - move closer
Backward - move further
Right - move right
Left - move left

Note: When you move the camera right or left, the world will appear to move in the opposite direction.


 and 
Use WALK+TURN to change the angle of the camera in a world.

Forward - turn upward
Backward - turn downward
Right - turn to the right
Left - turn to the left


 and 
Use FLY+PLAN to move left or right.

Forward - move the camera forward towards its longitudinal axis
Backward - move the camera backward
Right - turn the camera to the right around its vertical axis
Left - turn the camera to the left around its vertical axis

Note: The camera's vertical axis may be inclined in a 3D Space.
Move the mouse while holding down the ALT key to switch FLY+PAN.
Move the mouse while holding down the Space key to switch FLY+TURN.
Move the mouse while holding down the ALT+Space keys to switch FLY+ROLL.


 and 
Use FLY+PAN to move up, down, left, or right within a single vertical plane.

Forward - move up
Backward - move down
Right - move right
Left - move left

Note: When you move the camera, the world will appear to move in the opposite direction.

 and 
Use FLY+TURN to turn the camera.

Forward - turn the camera upward around its horizontal axis
Backward - turn the camera downward around its horizontal axis
Right - turn the camera to the right around its vertical axis
Left - turn the camera to the left around its vertical axis


 and 
Use FLY+ROLL to incline the camera.

Right - incline to the left
Left - incline to the right


 and 
Use STUDY+PLAN to examine an object from various angles.


Forward - move the camera forward
Backward - move the camera backward
Right, Left - move the camera around the point which is defined by the pointer position where you press the left mouse button. If there is no any face there, the scene coordinate origin is considered.


 and 
Use STUDY+TURN to examine an object from various angles.

Select STUDY and TURN from the vertical toolbar. Position the pointer over the object you'd like to examine. Press the left mouse button. Drag the mouse to move the camera around the point on the object where you press the button.
Note: Move the mouse while holding down the ALT key to switch STUDY+ROLL.
Move the mouse while holding down the Space key to switch STUDY+PLAN.
Move the mouse while holding down the ALT+Space keys to switch STUDY+PAN.

 and 
Use STUDY+ROLL to incline the camera around the selected point. Select STUDY and Roll from the vertical toolbar. Position the pointer over the object. Press the left mouse button. Drag the mouse to incline the camera around the point on the object where you press the button.

Right - incline to the left
Left - incline to the right



Use GOTO to move close to object in a world. Select GOTO in the toolbar and then click on an object in the world. You'll move directly to it.

Restore, Fit, and Align

Cortona provides three mechanisms that can help to re-orient a camera if you have lost your way in a world. Unlike the navigation tools, these buttons invoke predefined actions that take place as you click on them. 

 
Use RESTORE to automatically return to the loaded world's original active viewpoint.

 
Use FIT to make the scene view fully visible in the Cortona 3D window.  

 
Use ALIGN to position the camera's horizontal and longitudinal axes parallel to the scene horizontal plane.  

Using Keyboard for Navigating

You can control the camera using keyboard commands. The functionality for arrow buttons corresponds to the movement of your mouse and depends on the navigation type and its option. Please note that the following description of keyboard commands is presented for the FLY+PLAN navigation.
  • Arrow Up - move closer.
  • Arrow Down - move further away.
  • Arrow Right - turn to the right.
  • Arrow Left - turn to the left.
  • Arrow Up on the numeric keypad - move closer.
  • Arrow Down on the numeric keypad - move further.
  • Arrow Right on the numeric keypad - move to the right. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
  • Arrow Left on the numeric keypad - move to the left. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
  • 7 on the numeric keypad - turn the camera downward around its horizontal axis.
  • 9 on the numeric keypad - turn the camera upward around its horizontal axis.
  • 1 on the numeric keypad - incline to the right. Note: It is not available in WALK mode.
  • 3 on the numeric keypad - incline to the left. Note: It is not available in WALK mode.
  • Gray Plus - move up in the case of FLY mode.
  • Gray Minus - move down in the case of FLY mode.
  • 1 on the alphanumeric keyboard - incline to the right. Note: It is not available in WALK mode.
  • 2 on the alphanumeric keyboard - incline to the left. Note: It is not available in WALK mode.
  • 3 on the alphanumeric keyboard - turn downward. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
  • 4 on the alphanumeric keyboard - turn upward. If the STUDY mode - move camera around the selected point or coordinate origin of the scene.
  • Page Down - next viewpoint.
  • Page Up - previous viewpoint.

To accelerate the camera's movement or rotation: Press SHIFT, CTRL or SHIFT+CTRL and one of the above keys simultaneously.

The ALT and SPACE keys allow the user to quickly change the navigation option to PAN and TURN accordingly in the FLY navigation mode (to ROLL and PLAN in the STUDY mode). The ALT and SPACE keys simultaneously pressed activate ROLL in the FLY navigation mode or PAN in STUDY.

Setting Cortona Options

The following options are supported from the pop-up menu of 3D window:
  • Viewpoints.  Activates a list of the predefined viewpoints.
  • Headlight.  Cortona automatically includes a light for the viewer in every world. The headlight always shines directly in front of the camera. You can switch the headlight on and off.
  • Navigation.  You can select a navigation mode.
  • Speed.  Controls the rate at which a camera moves through a world.
  • Full Screen.  This hides most screen elements so that you can view the whole scene. To close Full Screen, press ESC or F11.
  • Hide/Show Toolbars.  You can show or hide toolbars.
  • Show/Hide Console.  Shows or hides the VRML console containing errors or warnings (for VRML developers).
  • Preferences....  Modifies settings for Cortona VRML Client such as screen appearance, a renderer mode, and other options.
  • Help.  Lets you view the online help system and general information about Cortona.


To set Cortona preferences, choose Preferences... from the right-button pop-up menu. The ParallelGraphics Cortona Control dialog box is displayed.

Renderer

Allows you to select a rendering mode. To draw the 3D image, Cortona provides two hardware renderers: OpenGL and DirectX. If your system has hardware acceleration for either OpenGL or Direct3D (note: you must have DirectX 5 or greater installed), choose the appropriate renderer. Using hardware renderers can introduce limitations. Select a renderer to compare the performance and visual quality of hardware versus software rendering and set your preferences accordingly.

Renderer options

  • Wireframe rendering mode.  The object appears to be outlined with wires rather than solid.
  • Dither colors if needed. Controls whether Cortona dithers while rendering. Dithering improves the quality of rendering, but may lower performance.
  • Motion blur effect. Apply a motion blur effect. This actually makes an image seem a little blurred in motion.
  • Anti-aliasing. The technique for smoothing out jaggies in showing curves on computer monitor. There are two different modes: Idle-time and Real-time. If the Idle-time option is on, it is applied only for static scene. Whereas selecting Real-time initiates smoothing even in the viewer movement but results in decreasing frame rate.
  • Optimize texture for speed. All textures are optimized for speed.
  • Optimize texture for quality. All textures are optimized for quality. Note that if you select both Optimize texture for speed and quality, the renderer uses the available resources to optimize speed and quality simultaneously.
  • Do not render textures. To turn the textures on or off.
  • Use textures mip-mapping. When the scene contains acutely angled polygons that disappear into the distance, mixes low- and high-resolution versions of the same texture to reduce the jagged effect.
  • Automatic level of detail. Automatically reduces the number of polygons which are displayed for any object at large distances (tiny objects on computer screen) from the viewer.
  • Phong lighting model. A particular method for computing the apparent color of a face at a particular point. It improves the quality of lighting, but lower performance. Note that this option is available only for R98 Renderer in the Intel Pentium III optimization mode.


Collision detection.  By default, Cortona will allow you to pass through objects in your path. To prevent from passing through objects, click Always in the Collision detection box at the Navigation tab.
Background color.  You can change a background color of Cortona 3D window: Click the Background color box at the General tab, click the desired color from the palette, and then click OK.
VRML authors can also control a color that simulates ground and sky.

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